Single-Molecule Electrochemiluminescence Imaging of Plasmonic Hot Spot Reactivity

Localized surface plasmon resonance (LSPR), an important optical property of noble metal nanomaterials, is extensively applied in electrochemistry. However, the specific LSPR effects on metallic nanoparticles are difficult to unravel and evaluate, owing to simultaneous factors like intrinsic electroactivity and surface interactions. Herein, we designed a series of shell-isolated nanostructures, with mesoporous silica shells and plasmonic Au Nanorod cores (AuNR@mSiO₂), for precisely investigating both LSPR and nanoconfinement effects. Single-molecule electrochemiluminescence (ECL) imaging was employed to monitor the in situ turnover frequency (TOF) of photon emissions on individual plasmonic nanoamplifiers to determine the dominant factors influencing LSPR and nanoconfinement effects. TOF heatmaps and super-resolution ECL images unveiled distinct hot spot distributions along the plasmonic nanostructures. Our approach provides insight into and in-depth understanding of plasmonic effects during electrochemical reactions, thereby facilitating precise electrocatalyst design based on the physiochemical properties of LSPR.